(1) Field of the Invention
This invention relates to sialosylcerebrosides, and more particularly to sialosylcerebrosides contained in ganglioside sphingoglycolipids and a preparation method thereof.
(2) Description of the Prior Art
Glycolipids found in mammal cells are glycosides between ceramides, which are sphingosines (long chain amino alcohols) to which aliphatic acids have been attached through an amide linkage, and one or more sugars such as glucose, galactose, N-acetyl glucosamine, N-acetyl galacotosamine, fucose, sialic acid, etc. Among these glycosides, those containing sialic acid are called gangliosides.
Gangliosides exist mainly in the outer molecular layer of double molecular layers of the mammal cell membrane. Recent studies show that gangliosides play important roles in reception and recognition of, and response to, information in cells, receptor mechanism, differentiation, cell propagation, malignant cell transformation, cell behavior etc.
Among these compounds, sialosylcerebroside GM.sub.4 is contained in large amounts in the gray substance of human encephalon and sialosylcerebroside GM.sub.4 is considered a distinctive component of myelin membrane. These acidic glycolipids are found in erthrocyte of mouse, renal of rat and yolk of egg.
However, the function of ganglioside glycolipids as a cell membrane component has not been studied sufficiently and it is very difficult to isolate and purify sialosylcerebroside GM.sub.4 from an organism. Therefore precise synthesis of such sialosylcerebrosides containing sialosylcerebrosides GM.sub.4 is necessary for investigation of the function of ganglioside glycolipids as a cell membrane component.